Vacuum cleaner with suction indicator

ABSTRACT

A vacuum cleaner has an adjustable-height suction nozzle. A diaphragm switch is mounted in the housing inside the nozzle and determines a differential air pressure of the operating vacuum cleaner. Voltage source terminals are self-energizing with the rotation of a rotatable brush inside the nozzle and an indicator lamp is illuminated, or extinguished, upon developing a proper suction as establised by the proper adjusted height of the nozzle relative to the floor surface. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

BACKGROUND OF THE INVENTION

Vacuum cleaners have previously been proposed wherein there was anautomatic height adjustment of the nozzle relative to the floor, such asshown in U.S. Letters Pat. Nos. 2,555,887; 2,583,054; 2,592,710: and4,706,327. These were usually sufficiently complicated mechanisms thatthey were not commercially successful.

Vacuum cleaners have also been proposed utilizing a diaphragm to sensethe amount of vacuum either to vary a resistance, as in U.S. Pat. No.4,021,879, to slow the electric motor, or to actuate indicator lamps asdisclosed in U.S. Pat. Nos. 4,199,838 and 4,481,692.

Other vacuum cleaners have been proposed which utilize some form ofsensor to indicate when the filter bag is full and requires changing asin U.S. Pat. Nos. 4,199,838 and 4,342,133. Still other patents have hadsome form of indication of brush speed, either by a Hall effect sensor,as in U.S. Pat. No. 4,245,370, or by a magnet and sensor coil, as inU.S. Pat. Nos. 4,692,754 and 4,728,942.

SUMMARY OF THE INVENTION

The problem to be solved, therefore, is how to construct a vacuumcleaner with a suction indicator such that the proper height of anadjustable suction nozzle relative to the floor may be readilydetermined.

This problem is solved by a vacuum cleaner having a suction nozzle inletfor cooperation with a surface to be cleaned comprising, in combination,the height of the nozzle relative to a surface to be cleaned beingvariable, means to determine a differential air pressure of theoperating vacuum cleaner, an electrical switch actuated in accordancewith said differential pressure means, voltage source terminals, andindicator means connected electrically to said voltage source terminalsand said switch.

The problem may further be solved by a vacuum cleaner comprising, incombination, a nozzle connected to said vacuum cleaner for cooperationwith a surface to be cleaned, a rotatable brush in said nozzle, means toadjust the height of the nozzle relative to a surface to be cleaned, apermanent magnet on said rotatable brush, a pickup coil mounted in astationary manner on said nozzle for cooperation with said rotatablepermanent magnet to generate an alternating voltage, a diaphragm switchhaving a diaphragm and first and second electrical contacts, meansconnecting one side of said diaphragm to atmosphere, means connectingthe other side of said diaphragm to the low pressure condition of saidvacuum cleaner, an indicator, and means connecting said pickup coil tosaid diaphragm switch and said indicator.

The problem may still further be solved by a vacuum cleaner operatingcondition indicator with the vacuum cleaner having a rotatable brush ina heightadjustable nozzle comprising, in combination, a unitary housing,first and second indicator lights mounted in said housing, a diaphragmswitch having a diaphragm and mounted in said housing, means mountingsaid housing in said height-adjustable nozzle with said indicator lightsexternally visible, means to apply the differential air pressure of thenozzle of the vacuum cleaner to opposite sides of said diaphragm, apickup coil mounted in said housing and having a pole piece adapted forcooperation with a magnet rotatable with the brush of the vacuumcleaner, means connecting said pickup coil directly to said firstindicator light to be illuminated upon sufficient brush rotationalspeed, and means connecting said pickup coil in series with saiddiaphragm switch and said second indicator light to change the indicatorcondition thereof upon proper spacing of the vacuum cleaner nozzle to asurface to be cleaned to establish the differential air pressure toactuate said switch.

Accordingly, an object of the invention is to provide a self-poweredsuction indicator which requires no electrical connection from the motoror the energization source of the motor. Accordingly, such suctionindicator may be used with a vacuum cleaner having a removable nozzlewithout need for disconnecting any electrical connections.

A feature of the invention is to provide a small housing which fitswithin the suction nozzle of an upright vacuum cleaner. This nozzle alsocontains a rotatable brush, and the rotation of the brush is utilized todevelop a voltage to energize the suction indicator. In this manner, theindicator may have two functions of indicating proper rotation of thebrush, and also providing power to indicate the proper amount of suctiondeveloped when the adjustable nozzle is at the most advantageous spacingfrom the floor or other surface to be cleaned. A diaphragm switch isutilized to be actuated between ON and OFF conditions, depending on theamount of suction developed in the nozzle relative to the ambient. Thesmall housing may be completely concealed within the nozzle of thevacuum cleaner and the indicator be visible externally of the nozzle.The indicator may be indicator lamps for brush rotation speed and forproper amount of suction for most effective cleaning.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a part of a vacuum cleaner embodying theinvention;

FIG. 2 is a sectional view on line 2--2 of FIG. 1;

FIG. 3 is a front elevational view of an indicator housing;

FIG. 4 is a sectional view on line 4--4 of FIG. 3;

FIG. 5 is a top plan view of the housing of FIG. 3;

FIG. 6 is a front elevational view, similar to FIG. 3, of an alternativeembodiment of the invention; and

FIG. 7 is a sectional view on line 7--7 of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The figures of the drawing illustrate a vacuum cleaner 10 which may be acanister or tank-type, but has been illustrated as an upright householdelectric vacuum cleaner having a motor enclosure 11 and anadjustable-height suction nozzle 12. In this preferred embodiment, thenozzle 12 is also removable by releasing a latch 13. This exposes adrive shaft 14 from the motor 15. This motor may be the usual electricmotor energized from a source of commercial power frequency (not shown)and the motor drives a fan 16, acting in this case as a suction pump toestablish a suction through a suction conduit 17 of the nozzle 12 at thearea of attachment to the motor enclosure 11. This suction or region oflowered air pressure is present within the nozzle 12 and draws airthrough the nozzle inlet opening 18. The nozzle 12 also contains arotatable brush 20 which is driven through a belt 21 from the driveshaft 14, and should rotation of the brush be blocked with the motorrunning, the drive train for the brush is capable of slipping, e.g.,slipping at the junction of the belt 21 and shaft 14.

The height or spacing of the nozzle relative to the floor or othersurface to be cleaned is variable. A height-adjustment mechanism of aknown type may be utilized, such as that disclosed in U.S. Pat. No.4,078,275, the disclosure of which is hereby incorporated by reference.The exact type of height-adjusting nozzle mechanism is not critical, andthe mechanism shown in the aforementioned patent is merely illustrativeof one of many height-adjusting mechanisms. This mechanism incorporatesgenerally a pedal 24 which, when depressed to the phantom position,lowers a skid or wheel 25 which supports the vacuum cleaner 10 relativeto the floor. By so depressing the pedal 24 around the pivot shaft 26,the wheel is lowered and the vacuum cleaner suction nozzle 12 is raisedto its maximum extent. In this position, the air readily is admitted tothe suction nozzle inlet 18 so that the vacuum or lowered air pressurewithin the nozzle 12 is of a low value. An escapement pedal 27 may berepeatedly depressed against the urging of a spring 28 to release anescapement pawl 29 relative to a ratchet 30. Each depression of theescapement pawl 29 lowers the suction nozzle inlet incrementally untilthe suction inlet 18 is resting on the floor. With the suction inletcompletely closed off, a considerable vacuum may be developed inside thenozzle 12 by the fan 16. For example, this might be in the order of 12to 15 inches of water as a differential air pressure relative to theambient. It has been found that if the nozzle 12 is closely spaced offthe rug or other surface to be cleaned, a desirable high rate of airflow is created between the nozzle inlet and through the pile of thecarpeting for a maximum cleaning effect, and this could result in apressure differential equal only to two or three inches of water insteadof the full nozzle down pressure of 12 to 15 inches of water. Suchnozzle height will vary in accordance with the type of surface, whetherit be a plush, medium, low, loop, sculptured, or undulating pile typecarpet, a hard surface bare floor, and the like, but two to three inchesof water as a differential air pressure has been found to be the bestsuction cleaning condition for most dirty air-type upright cleaners forgeneral home cleaning, and may be higher for clean air uprights,canisters, and central vacuum units.

An indicator housing 38 is mounted against the rear wall of the nozzle12 by a single screw 39, the screw being normally hidden beneath arubber bumper 40. FIGS. 3, 4, and 5 better show the construction of theindicator housing 38 and FIG. 2 shows generally its position within thenozzle 12. The housing 38 has first and second indicators 41 and 42,shown as lamps, to indicate brush rotation and the best suctioncondition, respectively. The housing 38 is a unitary housing of someinsulating material, such as plastics. A pole piece 45 is fixed in thehousing 38, with a pickup coil 46 surrounding this pole piece. With thehousing 38 mounted within the nozzle 12, the pole piece is positionedclose to the rotating brush 20, on which a permanent magnet 47 islocated to sweep past the pole piece 45 and develop a voltage at voltagesource terminals 48 and 49 upon rotation of the brush 20. These voltagesource terminals 48 and 49 are connected by conductors 50 and 51 to thefirst indicator lamp 41 to illuminate this lamp upon rotation of thebrush. This lamp is visible behind a transparent or translucent lens 53,as shown in FIG. 1, and indicates rotation of the brush. Should theadjustable nozzle 12 be positioned too closely to the surface to becleaned, the rotatable brush may strike the carpet or other material,slowing, or even stopping, such brush due to the slippable drive train,with slipping primarily between the belt 21 and the motor shaft 14. Insuch case, a voltage ceases to be produced at the voltage sourceterminals 48 and 49, and the indicator lamp 41 will be extinguished.

A diaphragm switch 54 is mounted within the housing 38, and is anelectrical switch responsive to the operating condition of the vacuumcleaner 10. In this embodiment, it is responsive to a suction condition,namely, the lower air pressure within the nozzle 12 relative to theambient. The housing 38 has a circular shoulder 55 against which a firstface 62 of a circular, flexible diaphragm 56 is located. An insert 57 ofsolid insulating material is located in the housing 38 and in engagementwith a second face 63 of the diaphragm 56. A first terminal 58 is fixedon the insert 57, and is secured to a metal contact disc or blade 60 onthe second face 63 of the diaphragm to be deflectable therewith. Asecond terminal 59 is mounted on the insert 57 and, as shown, may beadjustable by having an adjustment screw 61 passing through the insertto be selectively engageable by the contact disc 60.

The shoulder 55 of the housing 38 cooperating with the first face 62 ofthe diaphragm 56 creates a first pressure chamber 64. In thisembodiment, this first pressure chamber is open to the ambient by meansof a port 65, which extends through an aperture 66 in the wall of thenozzle 12. An optional 0-ring 67 may be used to prevent air leakage atthis aperture 66. The insert 57 has an annular flange 69 which is sealedto the second face 63 of the diaphragm 56 to establish a second pressurechamber 70. This second pressure chamber is exposed to a lower pressureoperating condition of the operating vacuum cleaner 10 by means of aconduit 71 which is exposed to the lower air pressure inside the nozzle12. A filter 72 is provided inside the conduit 71 to help keep dust andother contaminants from inside the pressure chamber 70. This filter 72is preferably removable for cleaning, and the conduit 71 is aligned withthe contact disc 60. This provides physical protection to the flexiblediaphragm 56 so that should someone poke a pin or other object into theconduit 71 for cleaning, it will not puncture the diaphragm 56.

The terminals 58 and 59 of the diaphragm switch 54 are connected incircuit with the voltage source terminals 48 and 49. The voltage sourceterminal 48 is connected to the terminal 58 by the conductor 50. Thecircuit proceeds through the diaphragm switch from terminal 58 to 59,and then, by a conductor 74, to the second indicator lamp 42. The otherlead of this lamp is connected by a conductor 75 and conductor 51 to thevoltage source terminal 49. By this connection, when the diaphragmswitch 54 is closed, the voltage source terminals 48 and 49 willilluminate the second indicator lamp 42.

When the vacuum cleaner 10 is first turned on for use, the operator maydepress the pedal 24 to raise the nozzle 12 to its maximum heightrelative to the floor. With the motor 15 energized and running, therotatable brush 20 will be rotating at approximately its maximum speedbecause the brush will not be in contact with the carpet, and also thenozzle inlet opening 18 will be considerably spaced from the floorsurface to offer little obstruction to intake of air. The rotatingpermanent magnet 47 will then generate a voltage at the voltage sourceterminals 48 and 49, and the first indicator lamp 41 will beilluminated, for example, with a green light, to indicate rotation ofthe rotatable brush 20. Should this light not be illuminated, it mightindicate a jammed brush or broken belt 21. Thus, the operator of thevacuum cleaner is alerted to any defective conditions. Next, theescapement pedal 27 should be progressively depressed to graduallyincrementally lower the nozzle 12 toward the floor surface. This willincreasingly choke off intake of air as the nozzle inlet opening 18moves downwardly toward the correct operating position of the adjustableheight nozzle. At the proper operating height, the rotatable brush 20will be brushing the carpet, and the inlet opening 18 will besufficiently restricted to develop a low pressure area inside the nozzle12 of approximately two to three inches of water. The height of thenozzle relative to the floor surface for this proper operating conditionwill vary in accordance with the type of floor surface, but with thistwo to three inches of water as a differential air pressure, theflexible diaphragm 56 will be deflected sufficiently that the contactdisc 60 engages the adjustable screw 61. This closing of the switch willilluminate the second indicator lamp 42, which may be a red indicatorlamp, for example, visible behind a lens as shown in FIG. 1. This willbe a readily visible indication to the operator of the vacuum cleanerthat the adjustable height nozzle is set for maximum cleaning efficiencyfor the particular type of floor surface.

An alternative mode of operation could also be employed, as follows.With the suction inlet completely closed against the surface to becleaned, a considerable vacuum inside the nozzle will be developed bythe motor-fan system. For example, it could be as high as 15 inches ofwater lift as a pressure differential. Although there will be a smallamount of air flow through the carpet pile, it would not be sufficientto do a good cleaning job. The second indicator light 42, possibly redin color, will be lighted due to the diaphragm pressure switch closing,thus indicating poor cleaning. Raising the nozzle incrementally wouldcause the light 42 to extinguish, at which point the differential ofpressure will have dropped off and air flow permitted to increase,providing maximum cleaning condition.

A third embodiment is illustrated in FIGS. 6 and 7 as an indicatorhousing 80, with reference numerals the same as in FIGS. 3 and 4 for thesame parts. A third indicator 81 is added, which may be yellow ororange. This indicator is energized by conductor 75 and a new conductor82 leading to voltage source terminal 49. A second contact 83 isnormally closed against a diaphragm contact blade 84 on the atmosphericside of the diaphragm 56. Contact 83 is connected to a terminal 85,which is connected by a conductor 86 to the indicator 81.

In operation, the indicator 41 would be the rotation indicator, asbefore. The indicator 42 would again be a red lamp. With the cleanerturned "on" and brush roll running and nozzle height fully up, the brushroll turn indicator 41 would be lighted as before, but so would theorange/yellow light 81. Lowering the nozzle incrementally to the desiredheight would turn the red light 42 on and orange/yellow light 81 off.This is functionally the same as the concept in the first embodiment,except that the third light 81 indicates to the operator that the nozzleis too high to clean properly.

It will be noted that the voltage source terminals 48 and 49 are capableof developing a voltage when the nozzle 12 is attached to the motorenclosure 11 and the brush 20 rotates. The nozzle 12 is removable fromthe motor enclosure 11, and there are no electrical connections betweenthe motor enclosure 11 and nozzle 12. Thus, the nozzle 12 may be removedso that the motor shaft 14 and/or suction fan 16 may be used for otherapplications. The indicator means 41, 42 and 81 and the voltage sourceterminals 48 and 49 are mounted in the removable nozzle 12, with anabsence of all electrical connections from the motor enclosure to thenozzle. The rotating permanent magnet 47 is a means to develop a voltagein cooperation with the pickup coil 46 in accordance with rotation ofthe brush 20. The indicator housing 38 or 80 is small and easily mountedinside the nozzle 12 by the single screw 39. The port 65 passing throughthe aperture 66 helps orient the housing 38 for proper positioning. Thehousing is therefore hidden inside the nozzle 12, but the indicatorlamps 41, 42, and 81 are visible externally of the nozzle 12 to thevacuum cleaner operator through apertures such as apertures 77 in thetop of the nozzle 12. A curable plastics material 78 may be filledinside the housing 38 to cover the insert 57 and help seal the insert tothe diaphragm 56 and also to provide protection to the relatively smallgauge conductors 50, 51, 74, and 75. This makes a rugged housing whichis sealed except for the port 65 and conduit 71 for easy handling duringproduction and assembly.

The present disclosure includes that contained in the appended claims,as well as that of the foregoing description. Although this inventionhas been described in its preferred form with a certain degree ofparticularity, it is understood that the present disclosure of thepreferred form has been made only by way of example and that numerouschanges in the details of construction and of the circuit and thecombination and arrangement of parts and circuit elements may beresorted to without departing from the spirit and the scope of theinvention as hereinafter claimed.

What is claimed is:
 1. A vacuum cleaner having a suction nozzle inletfor cooperation with a surface to be cleaned, comprising incombination:means for variably adjusting the height of the nozzlerelative to a surface to be cleaned; means to sense a differential airpressure between that of the atmosphere and that within the nozzle ofthe operating vacuum cleaner; an electrical switch actuated in responseto said differential pressure sensing means sensing a predeterminedlevel of differential pressure; a voltage source including terminals onthe nozzle; and indicator means connected electrically to said voltagesource terminals through said switch whereby said indicator indicates tothe operator that the height adjustment of the nozzle is proper due tothe magnitude of the differential pressure a suction for most effectivecleaning.
 2. The vacuum cleaner as set forth in claim 1, including arotatable brush driven by a motor through a slippable drive; andmeans todevelop a voltage at said voltage source terminals in response torotation of the brush and with no electrical connection to the motor orto the energization source of the motor.
 3. The vacuum cleaner as setforth in claim 1, including an electric motor energizable from acommercial frequency power source, the motor driving a fan to create asuction, said motor being in an enclosure with said nozzle beingremovable therefrom, there being an absence of all electricalconnections from said motor enclosure to said nozzle; andsaid indicatormeans and voltage source terminals being mounted in said removablenozzle.
 4. The vacuum cleaner as set forth in claim 3, including arotatable brush in said nozzle; andmeans to develop a voltage at saidvoltage source terminals in response to rotation of said brush.
 5. Thevacuum cleaner as set forth in claim 1, wherein said differential airpressure sensing means is mounted within said nozzle and is responsiveto the difference in air pressure between said nozzle and the ambient.6. The vacuum cleaner as set forth in claim 1, wherein said differentialpressure sensing means includes a deflectable diaphragm; andsaidelectrical switch being operable by said diaphragm.
 7. A vacuum cleanercomprising, in combination:a nozzle connected to said vacuum cleaner forcooperation with a surface to be cleaned; a rotatable brush in saidnozzle; means to adjust the height of the nozzle relative to a surfaceto be cleaned; a permanent magnet on said rotatable brush; a pickup coilmounted in a stationary manner on said nozzle for cooperation with saidrotatable permanent magnet to generate an alternating voltage; adiaphragm switch having a diaphragm and first and second electricalcontacts; means connecting one side of said diaphragm to atmosphere;means connecting the other side of said diaphragm to the air flowcircuit within said vacuum cleaner; a voltage energized indicator; meansconnecting said pickup coil to said indicator through said diaphragmswitch to energize said indicator, whereby said indicator indicates tothe operator that the height adjustment of the nozzle is proper due to apredetermined difference existing between atmospheric pressure andpressure within the air flow circuit with a suction for most effectivecleaning.
 8. A vacuum cleaner as set forth in claim 7, wherein saidindicator is a lamp.
 9. A vacuum cleaner as set forth in claim 7,including a housing for said pickup coil, diaphragm switch, andindicator.
 10. A vacuum cleaner as set forth in claim 9, including meansto secure said housing to said nozzle.
 11. A vacuum cleaner as set forthin claim 9, including means to secure said housing within said nozzle,with said indicator being visible externally of said nozzle.
 12. Avacuum cleaner as set forth in claim 7, wherein said indicator isenergized upon the nozzle being height-adjusted to within a maximumdistance from the surface to be cleaned.
 13. A vacuum cleaner as setforth in claim 7, wherein said indicator is de-energized upon the nozzlebeing height-adjusted more than a maximum distance away from the surfaceto be cleaned.
 14. A vacuum cleaner operating condition indicator withthe vacuum cleaner having a rotatable brush in a height-adjustablenozzle, comprising, in combination;a unitary housing; first and secondindicator lights mounted in said housing; a diaphragm switch having adiaphragm and mounted in said housing; means mounting said housing inheight-adjustable nozzle with said indicator lights externally visible;means to apply the differential air pressure of the nozzle of the vacuumcleaner to opposite sides of said diaphragm; a pickup coil mounted insaid housing and having a pole piece adapted for cooperation with amagnet rotatable with the brush of the vacuum cleaner; means connectingsaid pickup coil directly to said first indicator light to beilluminated in response to brush rotational speed; and means connectingsaid pickup coil in series with said diaphragm switch and said secondindicator light to change the indicator condition thereof upon properspacing, with a suction for most effective cleaning, of the vacuumcleaner nozzle to a surface to be cleaned to establish the differentialair pressure to actuate said switch.
 15. A vacuum cleaner operatingcondition indicator as set forth in claim 14, including said diaphragmbeing flexible;means sealing a first face of said diaphragm to saidhousing; and an insert secured to said housing and having an annularshoulder sealed to said second face of said diaphragm to form a lowpressure chamber.
 16. A vacuum cleaner operating condition indicator asset forth in claim 15, including a movable contact mounted to beactuated by said diaphragm and electrically connected to a first switchterminal; anda second switch terminal mounted on said insert.
 17. Avacuum cleaner operating condition indicator as set forth in claim 14wherein said differential air pressure applying means includesconduitmeans to apply the lower air pressure within the nozzle to the one sideof said diaphragm.
 18. A vacuum cleaner operating condition indicator asset forth in claim 17, including a filter in said conduit means.
 19. Avacuum cleaner operating condition indicator as set forth in claim 17,including a metal contact on the low pressure one side of said diaphragmas part of said switch.
 20. A vacuum cleaner operating conditionindicator as set forth in claim 19, wherein said conduit means isaligned with said contact for physical protection for said diaphragm.21. A vacuum cleaner operating condition indicator as set forth in claim14, including:a third indicator light in said housing; and a thirdelectrical contact on the other side of said diaphragm connecting saidthird indicator light to said pickup coil.